The Antioch woman was arrested on suspicion of attempted murder Monday after Los Angeles County sheriff's investigators said she used knives from the kitchen department of Target to stab random shoppers. An off-duty Los Angeles County sheriff's deputy who had been shopping for paper towels halted Trawick and detained her.

Her sister Stephanie, who asked that her last name not be used because she feared harassment, told The Times the family was worried that Trawick could act out violently after she began experiencing severe emotional problems in her 30s.

"They categorized her with different things. Her mood would change from day to day; one she would be normal and the next day, she's not," the sister said.

Family members said Trawick was in and out of the hospital with mental health issues. Her family "begged them [medical authorities] not to release her and send her to treatment," Stephanie said. "They did nothing. It was really frustrating."

Court records show that Trawick had numerous charges for mostly minor crimes, including public drunkenness, petty theft and vandalism. She also was arrested for misdemeanor assault, though details of that case were not immediately available.

Her sister acknowledged that Trawick had been troubled but attributed her problems to her mental illness, which manifested itself in violent thoughts but not violent actions, she said. And she never had received consistent treatment.

Trawick was a creative, gregarious woman when she was not consumed by dark thoughts, her sister said. She moved to the Los Angeles area a year ago and was living with friends, Stephanie said. "She did it on a whim, like a lot of things she did," the sister said.

The family was unsure why Trawick chose Target but said she had visited a Target in Antioch with family about a week before the attack.